There are just two note grouping patterns (if you can count the 1st one), and the whole snare drum piece uses various combinations of these.
Most beginners pick this up quite quickly, and it’s a great way for them to understand the ‘twice as fast’ speed difference between quarter notes and eigth notes (crotchets and quavers). It’s also a good idea to introduce the metronome when it’s sounding good, starting at about 60 or 70 beats per minute and going up to 110 or more.
Related (Premium): The Level 1 book included in the download is slightly harder than this sheet – 10 Snare Drum Pieces – Book 1